Regional portrayal with multi-pattern color dot maps.

Methods of portraying multiple distributions in the same map space are limited to a few, largely untested symbolization techniques. This paper investigates one of those techniques, the multi-pattern color dot map. A perception test is employed comparing the relative effectiveness of the multi-pattern map to single distribution dot maps in conveying'regional distribution information to map readers. Responses are analyzed with two measures: the consistency with which subjects defined region boundaries within the map; and the internal accuracy of regions identified. Results suggest that color dot maps are at least as effective as several single black and white dot maps in portraying regions. Les methodes pour produire une carte montrant la repartition de plusieurs phenomenes se resument a quelques techniques semiologiques peu verifiees. Cet article etudie une de ces techniques, la carte en couleurs par points a phenomenes multiples. On verifie a l'aide d'un test de perception l'efficacite des cartes a phenom...